C-Reactive Protein (CRP) is often used to support the differentiation between acute bacterial and viral infections, including acute meningitis. However, this is not always possible due to similar CRP concentrations upon presentation in these two cohorts. We have improved the diagnostic yield of this biomarker by adjusting its concentrations to the estimated time from disease onset, transforming a single, static value into a dynamic measurement, expressed in milligrams per liter per hour. Our study included 46 matched pairs of patients with acute bacterial and acute viral meningitis who were presented to the hospital with similar CRP concentrations (± 10%). Estimated CRP velocity (eCRPv) was calculated by dividing the first CRP measurement at the Emergency department (ED) by the estimated time of disease onset (iso-CRPinemic model). There was negligible difference (p = 0.4) between the mean ± s.d. CRP concentrations in the bacterial (110.1 ± 66.9 mg/L) versus the viral (110.0 ± 68.4 mg/L) group. However, when we adjusted these concentrations to the time from onset of the clinical picture of acute meningitis, it served to differentiate well (p < 0.001) between the groups. The diagnostic yield of CRP at presentation amongst patients with acute meningitis can be improved by adjusting the value to the estimated time from disease onset.
Matatyahu et al. (Thu,) studied this question.